ZLAVSY performs one of the matrix-vector operations
x := A*x or x := A'*x,
where x is an N element vector and A is one of the factors
from the block U*D*U' or L*D*L' factorization computed by ZSYTRF.
If TRANS = 'N', multiplies by U or U * D (or L or L * D)
If TRANS = 'T', multiplies by U' or D * U' (or L' or D * L')

DIAG is CHARACTER*1
Specifies whether or not the diagonal blocks are unit
matrices. If the diagonal blocks are assumed to be unit,
then A = U or A = L, otherwise A = U*D or A = L*D.
= 'U': Diagonal blocks are assumed to be unit matrices.
= 'N': Diagonal blocks are assumed to be non-unit matrices.

[in]

N

N is INTEGER
The number of rows and columns of the matrix A. N >= 0.

[in]

NRHS

NRHS is INTEGER
The number of right hand sides, i.e., the number of vectors
x to be multiplied by A. NRHS >= 0.

[in]

A

A is COMPLEX*16 array, dimension (LDA,N)
The block diagonal matrix D and the multipliers used to
obtain the factor U or L as computed by ZSYTRF.
Stored as a 2-D triangular matrix.

[in]

LDA

LDA is INTEGER
The leading dimension of the array A. LDA >= max(1,N).

[in]

IPIV

IPIV is INTEGER array, dimension (N)
Details of the interchanges and the block structure of D,
as determined by ZSYTRF.
If UPLO = 'U':
If IPIV(k) > 0, then rows and columns k and IPIV(k)
were interchanged and D(k,k) is a 1-by-1 diagonal block.
(If IPIV( k ) = k, no interchange was done).
If IPIV(k) = IPIV(k-1) < 0, then rows and
columns k-1 and -IPIV(k) were interchanged,
D(k-1:k,k-1:k) is a 2-by-2 diagonal block.
If UPLO = 'L':
If IPIV(k) > 0, then rows and columns k and IPIV(k)
were interchanged and D(k,k) is a 1-by-1 diagonal block.
(If IPIV( k ) = k, no interchange was done).
If IPIV(k) = IPIV(k+1) < 0, then rows and
columns k+1 and -IPIV(k) were interchanged,
D(k:k+1,k:k+1) is a 2-by-2 diagonal block.

[in,out]

B

B is COMPLEX*16 array, dimension (LDB,NRHS)
On entry, B contains NRHS vectors of length N.
On exit, B is overwritten with the product A * B.